Did you think of a question that could be studied, or make an observation that was interesting or unexpected? You should send it to the Question Board!

Discuss these questions with the people in your group:

1. Study the spectra of objects of various bright colors. Try to determine how their spectra are related to their colors -- how orange is different from green, or purple is different from yellow. Explain how to verify that grass is green and dandelions are yellow, using your spectroscope.
2. Suppose you arrange two overhead projectors so that they are illuminating the same white screen, and then put different colored filters on them. What color or colors appear on the screen where they overlap?  Red plus green makes .... what?
3. Even more fun is to find three overhead projectors, and have three beams (red, green and blue) illuminating the screen. (This will work best if you block any white light that your filter is not big enough to cover). What color will the screen be? How many shadows will an object have, and what color are they? What determines where the shadows are and what color they are?
4. One of our activities was called subtracting colors, while another was called adding colors.  Explain why we used the terms addition and subtraction.  What are we adding and subtracting?  What do you get if you add all the light together?  What about if you add all the color filters together?
5. When you mix paint of different colors, do you use the "color addition" or the "color subtraction" rules? The Sunday comics are printed on white paper using black ink and three colored inks. Which colors are used? Is this an example of color addition or color subtraction -- or some of each?
6. What color or colors of light does grass most likely need in order to grow? (This is not a biology question. It is a physics question, and the answer is contained in something you learned in this section).